The present invention relates to autonomous sensor systems and more particularly, to thermoelectrically powered autonomous sensor systems that transmit a sensor signal via wireless communication to a remote receiver.
Condition based maintenance is important to industry as well as the military for sustaining the performance of machine systems. As the machine systems become increasingly complex and expensive, substantial costs are typically associated with the maintenance of the systems. The lack of accurate monitoring often results in the maintenance being performed after a failure of the system. The potential for catastrophic failure as well as unscheduled downtime of the system, becomes an expensive component of operations. Therefore, maintenance is often performed prior to any failure, or need. While such premature maintenance typically avoids catastrophic failure as well as unscheduled downtime of the system, the premature maintenance represents a substantial amount of unnecessary labor and parts. Thus, the premature maintenance regime also increases costs.
To assist in maintenance scheduling, monitoring systems locate a sensor at a location that can be reached by a wire, cable or line for providing power and sending data. However, connecting the sensor to an interconnecting wire creates additional costs in the monitoring system as well as limits the available locations for the sensors. Incomplete coverage of relevant areas by wired sensors limits the available data and hence knowledge of the system condition.
Therefore, the need exists for an autonomous sensor assembly that can derive its power from the environment. The need also exists for an autonomous sensor assembly that can provide a signal corresponding to a sensed condition, as well as transmit the signal in a wireless communication. A need exists for a compact autonomous sensor that can be operably located without interfering with the monitored device.
The present invention provides an autonomous sensor system that can be powered by scavenged or dedicated thermal energy for sensing, generating and wirelessly communicating a signal corresponding to a sensed condition. The present invention thereby provides a compact autonomous sensor powered from an environmental energy source, wherein resulting signals are transmitted without requiring a cabled or wired interconnection. Thus, the present invention allows increased spatial distribution of sensors, while reducing installation costs. The autonomous sensor system can be employed on any of a variety of devices, including but not limited to pumps, compressor wheels, turbines, motors and generators.
The autonomous sensor system includes a thermoelectric module for converting scavenged or dedicated thermal energy from the operating environment to electricity. The generated electricity is used to power an associated sensor and transmit a corresponding signal.
The invention further contemplates signal conditioning or processing prior to transmission. The system can include digital signal processors located at the sensor, wherein the digital signal processors are powered by the locally generated electricity from the thermoelectric module.
The autonomous sensor system can be modularized for a given operating environment, thereby permitting ease of installation and sufficient coverage of a sensed area. Further, this autonomous sensor system can be retained in housings constructed for specific operating environments.